// This file is part of Substrate.

// Copyright (C) 2020 Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: Apache-2.0

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// 	http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! Metering primitives and globals

use lazy_static::lazy_static;
use prometheus::{
    core::{AtomicU64, GenericCounter, GenericGauge},
    Error as PrometheusError, Registry,
};

#[cfg(feature = "metered")]
use prometheus::{core::GenericCounterVec, Opts};

lazy_static! {
    pub static ref G_TOKIO_THREADS_TOTAL: GenericCounter<AtomicU64> =
        GenericCounter::new("tokio_threads_total", "Total number of threads created")
            .expect("Creating of statics doesn't fail. qed");
    pub static ref G_TOKIO_THREADS_ALIVE: GenericGauge<AtomicU64> =
        GenericGauge::new("tokio_threads_alive", "Number of threads alive right now")
            .expect("Creating of statics doesn't fail. qed");
}

#[cfg(feature = "metered")]
lazy_static! {
    pub static ref G_UNBOUNDED_CHANNELS_COUNTER : GenericCounterVec<AtomicU64> = GenericCounterVec::new(
        Opts::new("unbounded_channel_len", "Items in each mpsc::unbounded instance"),
        &["entity", "action"] // 'name of channel, send|received|dropped
    ).expect("Creating of statics doesn't fail. qed");

}

/// Register the statics to report to registry
pub fn register_globals(registry: &Registry) -> Result<(), PrometheusError> {
    registry.register(Box::new(G_TOKIO_THREADS_ALIVE.clone()))?;
    registry.register(Box::new(G_TOKIO_THREADS_TOTAL.clone()))?;

    #[cfg(feature = "metered")]
    registry.register(Box::new(G_UNBOUNDED_CHANNELS_COUNTER.clone()))?;

    Ok(())
}
